A novel Li3Mg3NbO7 microwave dielectric ceramic with ultra-low loss

Novel ultra-low-loss Li3Mg3NbO7 ceramics were synthesized using solid-state reaction method. The microstructure, bond characteristics, and microwave dielectric properties (MDPs) of the Li3Mg3NbO7 ceramics were explored. Furthermore, the Li3Mg3NbO7 ceramics crystallized in the orthorhombic rock-salt structure and the optimized density (97.7%) was obtained at 1200 °C. Utilizing complex chemical bond theory (P–V-L theory) and Raman spectra, the connection between structure and properties was constructed. εr value was mainly affected by the ρrel and average ionic polarization. The UNb–O and packing fraction were the key internal factors influencing the Q × f value. The τf was intimately relevant to Nb–O bond and τε. Notably, the Li3Mg3NbO7 ceramics sintered at 1200 °C exhibited excellent MDPs (εr = 14.7, Q × f = 121,047 GHz, τf = −24.8 ppm/°C), offering enormous prospects for 5G/6G communication applications.